Artifacts In Magnetic Resonance Imaging and Computed Tomography Caused By Dental Materials

Ahmad Jaghsi,Thomas Klinke,Reiner Biffar,Juliane Maron,Amro Daboul,Tomasz Gredes,Ralf Puls,Martin W. Brechbiel

doi:10.1371/journal.pone.0031766

Abstract

BackgroundArtifacts caused by dental restorations, such as dental crowns, dental fillings and orthodontic appliances, are a common problem in MRI and CT scans of the head and neck. The aim of this in-vitro study was to identify and evaluate the artifacts produced by different dental restoration materials in CT and MRI images.MethodsTest samples of 44 materials (Metal and Non-Metal) commonly used in dental restorations were fabricated and embedded with reference specimens in gelatin moulds. MRI imaging of 1.5T and CT scan were performed on the samples and evaluated in two dimensions. Artifact size and distortions were measured using a digital image analysis software.ResultsIn MRI, 13 out of 44 materials produced artifacts, while in CT 41 out of 44 materials showed artifacts. Artifacts produced in both MRI and CT images were categorized according to the size of the artifact.SignificanceMetal based restoration materials had strong influence on CT and less artifacts in MRI images. Rare earth elements such as Ytterbium trifluoride found in composites caused artifacts in both MRI and CT. Recognizing these findings would help dental materials manufacturers and developers to produce materials which can cause less artifacts in MRI and CT images.

Highlights

Various kinds of materials are used in the dental treatment, materials such as metal alloys, composites, acrylics, porcelain and ceramics are used as filling materials and in dental prosthesis like crowns, dental bridges and dentures
The variations in the magnetic field strength that occur on the interface between the dental material and the adjacent tissues will cause magnetic field distortions and signal loss which will generate an artifact in the image
Artifacts produced in magnetic resonance imaging (MRI) and computed tomography (CT) were categorized according to the size and direction of the artifact. the artifact categories (Table 1) were in a similar manner to the classifications of Hinshaw et al [13] and Behr et al [4]

Summary

Introduction

Various kinds of materials are used in the dental treatment, materials such as metal alloys, composites, acrylics, porcelain and ceramics are used as filling materials and in dental prosthesis like crowns, dental bridges and dentures. The properties and specifications of these materials are well defined and studied Their influence and effect on image quality with computed tomography (CT) and magnetic resonance imaging (MRI) is not covered sufficiently in the literature. The presence of high attenuation metal objects in the field of view such as dental restorations, orthodontic bands, surgical plates and pins can cause this type of artifacts. Artifacts caused by dental restorations, such as dental crowns, dental fillings and orthodontic appliances, are a common problem in MRI and CT scans of the head and neck. The aim of this in-vitro study was to identify and evaluate the artifacts produced by different dental restoration materials in CT and MRI images

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